(1) Field of the invention
The present invention relates to an improved structure of a weatherstrip member for sealing an end portion of a pane of window glass applicable to a vehicular door, which assures a superior characteristic of sealing for the weatherstrip member against such a laterally slidable or longitudinally movable pane of the vehicular door window glass located on a corresponding sash portion of a vehicle body.
(2) Background of the Art
One of the conventional weatherstrip members described above will be described below.
It is noted that such weatherstrip members as described above are also referred hereinafter to as window glass run channels. Such glass run channels are attached to respective door window sashes formed on a vehicle body. Each glass run channel is made of integrally extruded rubber or synthetic resin such as polyvinyl chloride, both materials of which are integrally extruded. The glass run channel includes a bottom portion and a pair of side wall portions. These portions are integrally formed substantially in a letter U shape of cross section. In addition, both tips of the pair of side wall portions are formed with flexible seal lips slanted so as to face toward the bottom portion, respectively.
Furthermore, a surface of each seal lip slidably contacted with the corresponding end surface of the pane of the door window is treated with flocked fabrics in order to improve a water-proof characteristic and less noise propagation characteristic to the longitudinally movable pane of the door window glass and reduce a sliding resistance of the glass run channel against the pane of the door window glass when the pane of door window glass pane is moved so as to close the door.
However, since in the structure of the window glass run channel described above the flocked fabrics to treat the surface of each seal lip are processed after the extrusion of the window glass run channel is carried out, a man-hour (defined as a product of a number of persons and times required to complete a work) are additionally needed and manufacturing cost is accordingly increased.
It should be noted that although projections are formed on the surface of each seal lip along their elongated directions to simplify the structure of the window door glass run channel, such a kind of the structure is not necessarily sufficient to provide the water-proof characteristic and the high noise suppression characteristic and the structure provides the larger sliding resistance when the pane of window glass is moved longitudinally to engage the sash portion.
Next, a Japanese Utility Model Application First (unexamined) Publication Sho No. 60-11225 published on Jan. 25, 1985 exemplifies another but similar conventional structure of the window glass run channel.
In the above-identified Japanese Utility Model Application First Publication, one of the seal lips located at a vehicle outside portion needs to be relatively short and the other seal lip needs to be relatively long to provide the sealing on both sides of the tip of the pane of door window glass which is offset toward the vehicle outside portion from the center longitudinal line.
This is because as recent trends convexities and concavities of the whole surface of the vehicle body need to be reduced (so called, making the surface of the vehicle body flush) in order to improve an aero dynamic characteristic for the vehicle. In order to achieve such a flush surface of the vehicle body, the pane of window pane needs to be arranged so as to direct toward the outside of the vehicle body with respect to the sash portion of the vehicle body as outer as possible. Therefore, the end edge of the window door pane will be inserted in the sash portion at a position of the bottom of the sash portion offset from the center line thereof toward the outside portion.
However, in the conventional structure of the window glass run channel disclosed in the above-identified Japanese Utility Model Application First Publication, the longer one seal lip at the inner side of the vehicle body is deformed and bent from a connecting point, or base point, to the one of the side wall portion in the same way as the other seal lip at the outside portion of the vehicle body. Therefore, it becomes difficult to provide a sufficient sealing reaction force against the pane of window glass. In addition, only the tip portion of the one longer seal lip is contacted with the end edge of the pane of window glass under pressure in little face contact manner so that a failure in sealing thereat (leakage of water such as rain drops) will easily occur.
Furthermore, since the tip portion of the longer other seal lip is brought in contact with the bottom portion of the window glass run channel and then is unnaturally deformed, the failure in the sealing thereat will more easily occur during long use of such weatherstrip members.
Next, a Japanese Utility Model Application Second (Examined) Publication Sho No. 59-37373 published on Oct. 17, 1984 exemplifies still another but similar structure of the window glass run channel.
The window glass run channel disclosed in the above-identified second publication includes a main body retained in a retaining groove of the window sash portion substantially in a rectangular shape of cross section and two seal lips extended along the elongated direction of an upper surface of an upper wall of the main body. Two opposing concave grooves are formed on the main body which are engaged with respective inner end projected portions of inner and outer supporting pieces of the window sash portion. The inner and outer supporting pieces constitute the retaining groove. The pair of other seal lips are, furthermore, integrally extended from the concave grooves so as to slant upward to direct in the center position of the bottom portion, i.e., lower surface of the upper wall of the main body. The pair of the other seal lips are so structured that inner surfaces of the tips of the respective lips grasp and seal both side surfaces of an upper end portion of the pane of the window glass when the pane of window glass is moved in a space defined by the main body.
On the other hand, each seal lip on the upper wall of the main body is extended toward intermediate positions of the upper wall of the sash portion with respect to an extended line in line with a direction in which the window pane is inserted so as to form substantially in a letter Y shape of cross section on the sash portion. When the tip of the pane of window glass presses the lower surface of the upper wall of the main body, a tip portion of each seal lip placed on the upper surface of the upper wall depresses the corresponding bottom surface of the retaining groove so that it is deformed, thus a space defined by the upper surface of the main body and bottom surface of the window sash portion being sealed.
However, since in the above-described structure of the window glass run channel disclosed in the above-identified Japanese Utility Model Application Second Publication the tips of the seal lips formed on the center position of the upper surface of the upper wall of the main body are merely contacted with and stretched against the bottom surface of the retaining groove. Therefore, a sufficient sealing characteristic for the above-described space cannot be achieved and water or dust will leak and enter from the vehicle outside at the space. In addition, since the window glass is merely moved in the main body in the above-described direction, no contrivance is carried out to cope with the above-described flush surfacing of the vehicle body.